While the terms are often used interchangeably, cleaning and sanitation have two entirely different purposes.
Cleaning is the removal of unwanted material (commonly called soils) from production equipment and production areas. Removing leftover particles eliminates many microbes, their food source and other physical debris that can contaminate future batches of food. Appropriate cleaning chemicals may be applied manually or mechanically to equipment that remains assembled (clean-in-place) or that is partially or fully disassembled (clean-out-of-place). Most often, a combination of methods is used.
Sanitizing is the treatment of a clean surface with a chemical or physical agent (e.g., heat) to reduce microorganisms that cause disease and/or spoilage to levels considered safe for public health. By definition, sanitizing a food contact surface must reduce the population of specific bacteria by 99.999 per cent (a 5 log kill) in 30 seconds. Non-food contact surfaces require a reduction of 99.9 per cent (a 3 log kill), also within 30 seconds. When microbial populations are reduced to these levels, the surfaces are considered to be microbiologically clean.
It should be noted that sanitizers do not destroy all pathogens. For example, if there are 1 million bacteria per square centimetre, a 99.999 per cent (5 log) (The term "log" is an abbreviation of "logarithm." A logarithm is a "power of ten" (101)). Each logarithmic reduction reduces the microbial population by 90 per cent.kill still leaves 10 bacteria per square centimetre. Some of these may be pathogens or spoilage-causing organisms. Under optimal growing conditions (e.g., food, water, nutrients, and suitable pH, temperature and oxygen level), the population of the surviving bacteria may double every 20 minutes. Therefore, surfaces that are microbiologically clean immediately after cleaning and sanitizing operations may develop high bacterial levels if left undisturbed for a period of time (e.g., overnight). As a general rule, surfaces left for more than four hours must be sanitized again before production resumes.
Undesirable microorganisms (pathogens and/or spoilage-causing organisms) may come from:
- Ingredients (e.g., fruits and vegetables to be processed or packed)
- People (e.g., dirty hands)
- The building (e.g., dirt and condensation dripping from overhead pipes, dirty drains or unclean doorknobs) Equipment (e.g., packaging equipment, pallet truck travelling through the building, dirty buttons and switches, or dirty cleaning brushes
- Improperly stored garbage and product residues
- Pools of water on the floor
- Rodents and other pests
- The air (via aerosols)
- Many other source